Microwave heating construct

ABSTRACT

A blank for a construct comprises a main panel including a removable panel at least partially defined by a line of disruption, a plurality of side panels extending from the main panel along respective fold lines, and a microwave energy interactive element overlying at least a portion of the main panel. The blank may be used to form a construct capable of heating, browning, and/or crisping upper and lower surfaces of a food item.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of U.S. Provisional Application No.60/833,830, filed Jul. 27, 2006, which is incorporated by referenceherein in its entirety.

TECHNICAL FIELD

The present invention relates to blanks, constructs, and systems forcontaining, heating, browning, and/or crisping a food item in amicrowave oven.

BACKGROUND

Microwave ovens provide a convenient means for heating a variety of fooditems, including dough-based products such as pizzas and pies. However,microwave ovens tend to cook such items unevenly and are unable toachieve the desired balance of thorough heating and a browned, crispcrust. Many commercially available packages attempt to brown and/orcrisp the bottom surface of the food item without addressing the need tobrown and/or crisp the crust or dough on the top or edges of the fooditem. Thus, there is a need for a system that provides the desireddegree of heating, browning, and/or crisping of both the bottom and topsurfaces of the crust or dough of a food item.

SUMMARY

The present invention relates generally to various blanks, packages,containers, trays, pans, cards, disks, or any combination thereof(sometimes collectively “constructs”), various blanks for forming suchconstructs, methods of making such constructs, and methods of using suchconstructs to heat, brown, and/or crisp a food item in a microwave oven.

The various constructs of the present invention include one or morereconfigurable panels or portions that are adapted to contain the fooditem, for example, during shipping, sale, and storage, and to providebrowning and/or crisping of the food item when heated in a microwaveoven. Thus, for example, the construct may be a container thattransforms into a sleeve, heating disk, pouch, or any other suitablestructure. In one example, the construct comprises a package orcontainer that is capable of readily being transformed into a card ordisk for browning and/or crisping the bottom surface of a food item, forexample, the lower crust of a pizza or pie, and a cover, lid, or ringfor simultaneously browning and/or crisping another portion of the fooditem, for example, the top surface or upper edges of a pizza or pie. Theconstructs may include various features that enhance the heating,browning, and/or crisping of the food item including, but not limitedto, microwave energy interactive elements, apertures, venting channels,elevating elements, insulating elements, or any combination thereof.

According to various aspects of the invention, the transformation from astorage receptacle or container to a heating, browning, and/or crispingconstruct may comprise separating one or more portions of the container,folding one or more portions of the container or portions removedtherefrom, inverting one or more portions of the container or portionsremoved therefrom, any other transformation, or any combination oftransformations. In one particular aspect, the transformation comprisesproviding a package including a microwave energy interactive elementoverlying at least a portion of a surface thereof, separating a heating,browning, and/or crisping card or disk from the container, placing thefood item on the card or disk with the microwave energy interactiveelement facing the food item, inverting the remainder of the construct,and configuring the inverted portion to overlie the upper crust of thefood item with the microwave energy interactive element facing inwardlytoward the crust. In doing so, the heating, browning, and/or crisping ofboth the bottom surface and the top surface of the crust of the fooditem may be enhanced. The construct also may include side walls thatinclude a microwave energy interactive element that may enhance theheating, browning, and/or crisping of the sides of the food item.

In one particular aspect, a blank for forming a construct, comprises amain panel including a removable panel at least partially defined by aline of disruption, a plurality of side panels extending from the mainpanel along respective fold lines, and a microwave, energy interactiveelement overlying at least a portion of the main panel. The main panelmay include a peripheral portion that circumscribes the removable panel.The blank also may include a tab defined by a line of disruption thatinitiates and terminates proximate the removable panel.

In one variation of this aspect, the main panel is substantially squarein shape, and the plurality of side panels includes a first pair ofopposed side panels that are substantially rectangular in shape and asecond pair of opposed side panels that are substantially trapezoidal inshape. The blank may include a pair of end panels extending from opposedends of each side panel of the first pair of side panels.

In another variation, the plurality of side panels includes a first sidepanel including a pair of locking tabs extending from opposed ends ofthe first side panel, and a second side panel including a pair ofreceiving slits. Each receiving slit is adapted to receive one lockingtab of the pair of locking tabs.

In another variation, the plurality of panels includes a first set ofside panels and a second set of side panels extending from the mainpanel in an alternating relationship, each side panel of the first setof side panels includes a pair of locking tabs, and each side panel ofthe second set of side panels includes a pair of receiving slits adaptedto receive the respective adjacent locking tabs.

In one particular example, the main panel is substantially octagonal inshape, the first set of side panels includes four side panels, and thesecond set of side panels includes four side panels.

In this and other aspects of the invention, the microwave energyinteractive element may comprise a susceptor. If desired, the microwaveenergy interactive element may circumscribe a plurality of microwaveenergy transparent areas.

In another aspect, a construct for containing, heating, browning, and/orcrisping a food item comprises a base and a plurality of walls definingan interior space, and a microwave energy interactive material overlyingat least a portion of the base proximate the interior space. The basemay include a removable panel defined at least partially by a line ofdisruption and a peripheral area circumscribing the removable panel.

In one variation, the construct is adapted to receive a food item seatedon the base within the interior space. In another variation, themicrowave energy interactive material overlies at least a portion of theremovable panel, the removable panel is adapted to be separated from theconstruct, and with the removable panel separated from the construct,the removable panel is adapted to receive at least a portion of the fooditem intended to be browned and/or crisped.

In another variation, the microwave energy interactive material overliesat least a portion of the peripheral area of the base, the food itemincludes a peripheral area intended to be browned and/or crisped, and ina configuration with the walls extending downwardly from the base, theconstruct is adapted to receive the food item within the interior spacewith the microwave energy interactive material overlying the peripheralarea of the food item.

In one particular example, the base is substantially square in shape,and the plurality of walls includes a first pair of opposed walls thatare substantially rectangular in shape and a second pair of opposedwalls that are substantially trapezoidal in shape. The blank furthercomprises a pair of end panels extending from opposed ends of each wallof the first pair of walls.

In another particular example, the plurality of walls includes a firstset of walls and a second set of walls in an alternating relationshipextending from the main panel, each wall of the first set of wallsincludes a pair of locking tabs, and each wall of the second set ofwalls includes a pair of receiving slits adapted to receive therespective adjacent locking tabs.

In another aspect, a multi-use construct comprises a base and aplurality of walls defining an interior space. The base includes aremovable panel defined by a line of disruption. The construct alsocomprises a microwave energy interactive element overlying at least aportion of the base. The microwave energy interactive element defines atleast a portion of an interior surface of the construct. In a firstconfiguration with the walls extending upwardly from the base, theconstruct is adapted to receive and contain a food item within theinterior space. In a second configuration with the removable panelseparated from the base, the removable panel is adapted to receive atleast a portion of the food item. In a third configuration, theremovable panel is separated from the base, thereby forming a remainingportion of the construct. The remaining portion of the construct isadapted to be inverted relative to the first configuration andpositioned over the food item.

In one variation, the removable panel has a first side at leastpartially comprising at least a portion of the microwave energyinteractive element, the food item has a surface intended to be brownedand/or crisped, and in the second configuration, the surface of the fooditem intended to be browned and/or crisped is in a superposed, facingrelationship with the first side of the removable panel.

In another variation, the base includes a peripheral area circumscribingthe removable panel, the microwave energy interactive element overliesat least a portion of the peripheral area, and in the thirdconfiguration, the peripheral area overlies a portion of the food itemintended to be browned and/or crisped.

In yet another variation, the removable panel separated from the baseforms an opening in the base, and in the third configuration, theopening overlies a portion of the food item not intended to be brownedand/or crisped.

Other features, aspects, and embodiments of the invention will beapparent from the following description and accompanying figures.

BRIEF DESCRIPTION OF THE DRAWINGS

The description refers to the accompanying drawings in which likereference characters refer to like parts throughout the several views,and in which:

FIG. 1A is a schematic top plan view of an exemplary blank according tovarious aspects of the invention, having a square base panel;

FIG. 1B is a schematic perspective view of an exemplary tray formed fromthe blank of FIG. 1A, according to various aspects of the invention;

FIG. 1C is a schematic perspective view of the tray of FIG. 1Bcontaining a food item;

FIG. 1D is a schematic exploded view of the tray of FIG. 1B beingseparated into a heating, browning, and/or crisping disk and a heating,browning, and/or crisping ring, according to various aspects of theinvention;

FIG. 1E is a schematic exploded view of the heating, browning, and/orcrisping disk and ring of FIG. 1D in use with a food item;

FIG. 2A is a schematic top plan view of another exemplary blank that maybe used to form a construct according to various aspects of theinvention, having a substantially octagonal base panel;

FIG. 2B is a schematic perspective view of an exemplary tray formed fromthe blank of FIG. 2A, according to various aspects of the invention, inan inverted configuration;

FIG. 2C is a schematic exploded view of the tray of FIG. 2B separatedinto a heating, browning, and/or crisping disk and a heating, browning,and/or crisping ring, according to various aspects of the invention, inuse with a food item;

FIG. 3 is a schematic top plan view of a variation of the blank of FIG.2A, including a plurality of microwave energy transparent areas and aplurality of venting channels;

FIG. 4 is a schematic top plan view of another variation of the blank ofFIG. 2A, including alternate locking tabs and receiving slits;

FIG. 5A is a schematic cross-sectional view of an exemplary microwaveenergy interactive insulating material that may be used in accordancewith various aspects of the invention;

FIG. 5B is a schematic perspective view of the microwave energyinteractive insulating material of FIG. 5A, in the form of a cut sheet;

FIG. 5C is a schematic perspective view of the microwave energyinteractive insulating material of FIG. 5B, after sufficient exposure tomicrowave energy;

FIG. 5D is a schematic cross-sectional view of a variation of theexemplary microwave energy interactive insulating material of FIG. 5A;

FIG. 6 is a schematic cross-sectional view of another microwave energyinteractive insulating material that may be used in accordance with theinvention;

FIG. 7 is a schematic cross-sectional view of yet another microwaveenergy interactive insulating material that may be used in accordancewith the invention;

FIG. 8A is a schematic cross-sectional view of yet another exemplarymicrowave energy interactive insulating material that may be used inaccordance with various aspects of the invention; and

FIG. 8B is a schematic perspective view of the microwave energyinteractive insulating material of FIG. 8A, after sufficient exposure tomicrowave energy.

DESCRIPTION

The present invention may be illustrated further by referring to thefigures. For purposes of simplicity, like numerals may be used todescribe like features. It will be understood that where a plurality ofsimilar features are depicted, not all of such features necessarily arelabeled on each figure. It also will be understood that variouscomponents used to form the blanks and constructs of the presentinvention may be interchanged. Thus, while only certain combinations areillustrated herein, numerous other combinations and configurations arecontemplated hereby.

FIG. 1A depicts an exemplary blank 100 according to various aspects ofthe present invention. The blank 100 includes a plurality of adjoinedpanels. In this and other examples of the invention discussed hereinand/or contemplated hereby, each of the various panels and the blankgenerally has a first dimension, for example, a length, extending in afirst direction, for example, a longitudinal direction, D1, and a seconddimension, for example, a width, extending in a second direction, forexample, a transverse direction, D2. It will be understood that suchdesignations are made only for convenience and do not necessarily referto or limit the manner in which the blank is manufactured or erectedinto a construct.

Still viewing FIG. 1A, the blank 100 includes a main panel or majorpanel or base panel 102 comprising a removable portion 104 defined atleast partially by a line of disruption, for example, tear line 106. Inthis example, the base panel 102 is substantially square in shape andthe removable panel or portion 104 is substantially circular in shape.However, in this and other examples, the base panel and removable panelmay independently have any other desired shape, for example, circular,oval, triangular, square, rectangular, pentagonal, hexagonal,heptagonal, octagonal, or any other regular or irregular shape. Theshape of the various panels and the resulting construct may bedetermined by the shape of the food product, and it will be understoodthat different shapes are contemplated for different food products, forexample, sandwiches, pizzas, pastries, doughs, and so forth.

The removable portion 104 includes a tab 108 defined by a line ofdisruption, for example, cut line 110, which initiates and terminates atendpoints 112 proximate to tear line 106. In this example, cut line 110is substantially arcuate in shape, such that tab 108 is substantiallysemi-circular in shape. However, it will be understood that, in this andother examples, the tab may have any shape as needed or desired. Forexample, the tab may be oval, rectangular, square, diamond-shaped,trapezoidal, polygonal, or any other regular or irregular shape. Ifdesired, tear line 106 may be interrupted by a score line 114 thatextends substantially between endpoints 112.

Optionally, the removable portion 104 includes a plurality of scorelines or indentations 116 extending radially from a central area 118 ofthe panel 104. In this example, the blank 100 includes eightindentations. However, any number of such indentations may be used inaccordance with the present invention. Thus, for example, the blank mayinclude one, two, three, four, five, six, seven, eight, nine, ten, orany number of indentations as needed or desired for a particularapplication. Such indentations may serve as venting channels formoisture, as will be discussed further below. Alternatively, theindentations 116 may be formed in the opposite side of the panel 104 toform upwardly extending elongate protrusions.

Still viewing FIG. 1A, the blank 100 also includes a plurality of minorpanels or side panels extending from the base panel 104. In particular,the blank 100 includes a first pair of opposed side panels 120 joined tothe base panel 104 along respective fold lines 122, each of whichcorresponds generally to an edge of the substantially square base panel104. Side panels 120 are somewhat trapezoidal in shape, with fold lines122 having a length L1 less than the length L2 of panels 120 along edges124.

The blank 100 also includes a second pair of opposed side panels 126joined to the base panel 104 along respective fold lines 128, each ofwhich also corresponds generally to an edge of the substantially squarebase panel 104. Side panels 126 are substantially rectangular in shape,with fold lines 128 having a length L3 approximately equal to the lengthL4 of panels 126 along edges 130. A pair of opposed end panels 132 isjoined to each side panel 126 along respective fold lines 134. Endpanels 132 are separated from side panels 120 by respective cut lines orslits 136. If desired, end panels 132 may have tapered or “clipped”corners 138 to facilitate folding of the blank 100 into a container 144(FIG. 1B).

If desired, a microwave energy interactive element 140 may overlie atleast a portion of the blank 100, as shown schematically by stippling inFIG. 1A. The microwave energy interactive element may define at least aportion of a first surface 142 of the blank 100, and at least a portionof a first or interior surface 142 of a construct 144 formed from theblank 100, as shown schematically by stippling in FIGS. 1B and 1C. Inone example, the microwave energy interactive element comprises asusceptor. However, other microwave energy interactive elements, such asthose described below, are contemplated for use with the invention.

Turning now to FIG. 1B, numerous sequences of steps may be used to forma tray, package, container, or other construct 144 according to theinvention. In one example, end panels 132 may be folded toward sidepanels 126 along fold lines 134. Likewise, side panels 120, 126 may befolded toward the base panel 102 along respective fold lines 122, 128 toform somewhat upstanding members or walls, as shown in FIG. 1B. However,other sequences of folding are contemplated hereby. If desired, endpanels 132 may be joined to side panels 120 using an adhesive, a weld,or any other suitable technique.

In this configuration, the construct 144 comprises a tray that may beused to contain a food item F, for example, a pizza, fruit or meat pieor other pastry, or a sandwich, as shown in FIG. 1C. If desired, thetray 144 with the food item therein may be placed into an outer cartonor bag (not shown), or may be sealed with an overwrap (not shown).However, it will be understood that in some examples, the food item maybe provided separately from the tray, and/or the tray may be provided ina collapsed or flattened configuration.

To use the construct 144 according to one exemplary method, any fooditem F seated within the tray 144 may be removed. The user then may usea finger or other implement to apply pressure to tab 108, therebycausing it to fold or deflect away from the plane of the base panel 102along score line 114 (FIG. 1B). Next, grasping tab 108, the removablepanel 104 may be separated from the remainder of the construct 144 alongtear line 106, as shown in FIG. 1D, thereby forming a void or opening146 in the base panel 102. The remainder of the base panel 102 comprisesa peripheral area 148 that circumscribes the opening 146.

According to another aspect of the invention illustrated schematicallyin FIG. 1E, the removable panel 104 may be used as a heating, browning,and/or crisping card or disk 104. To do so, a food item F may be seatedon the disk 104 at least partially overlying the microwave energyinteractive element 140, for example, the susceptor. When the food itemF is heated in a microwave oven, the susceptor 140 converts microwaveenergy to thermal energy, which then can be transferred to the bottom ofthe food item F in proximate or intimate contact with the susceptor 140.As a result, the heating, browning, and/or crisping of the bottomsurface of the food item F may be enhanced. Further more, indentations116 may serve as venting channels that direct moisture away from thecenter of the food item, thereby further enhancing heating, browning,and/or crisping.

If desired, the remainder of the construct 144 may be used as a heating,browning, and/or crisping cover or somewhat square shaped “ring” 150 toheat, brown, and/or crisp at least a portion of the upper surface of thefood item F and, optionally, at least a portion of the sides of the fooditem F. To do so, the ring 150 may be inverted, thereby exposing asecond or outside surface of the ring 150 opposite the first or insidesurface 142, and positioned over the food item F with the microwaveenergy interactive element 140, for example, the susceptor, in intimateor proximate contact with the surface of the food item F to be heated,browned, and/or crisped. For example, where the food item is a pizza,the opening 146 generally may overlie the pizza toppings and theperipheral area 148 of the base panel 102 generally may overlie the topportion of the pizza crust. When the food item F is heated in amicrowave oven, the susceptor 140 converts microwave energy to thermalenergy, which then can be transferred to the top and/or sides of thefood item F to enhance heating, browning, and/or crisping of the fooditem F. Depending on the dimensions of the food item F and the ring 150,the ring 150 may be supported by side panels or walls 120, 126 (panels120 shown in FIG. 1D), or may rest directly on the food item F with thefood item F bearing the weight of the ring 150.

It will be understood that, in this and other embodiments of theinvention, the dimensions of base panel 102 and removable panel or disk104 (and therefore opening 146) may be selected to adjust which areas ofthe food item F are brought into proximate and/or intimate contact withthe microwave energy interactive element 140. For example, where it ismost desirable to brown and/or crisp the bottom surface of the food itemF, the removable panel or disk 104 may be dimensioned to be about thesame size as, or larger than, the bottom surface of the food item F.However, the resulting opening 146 formed in panel 102 may be so largethat a portion of the top surface of the food item to be browned and/orcrisped is exposed through the opening 146 and, therefore, not inintimate or proximate contact with the susceptor 140. Conversely, byreducing the size of the opening 146 to bring the top surface of thefood item F into closer proximity to the susceptor 140, the size of thedisk 104 is reduced. As a result, the food item F may extend beyond thedimensions of the disk 104 and may become less brown and/or crisp alongthe peripheral edges of the bottom surface. Further, the base panel 102may be dimensioned to bring the side panels or support elements 120, 126into closer proximity with the sides of the food item F, which mayfurther enhance heating, browning, and/or crisping of the areasproximate to the susceptor 140.

FIG. 2A depicts another exemplary blank 200 that may be used inaccordance with the invention. The blank 200 includes a main panel ormajor panel or base panel 202 comprising a removable portion 204 definedat least partially by a tear line 206. In this example, the base panel202 is substantially octagonal in shape and the removable panel orportion 204 is substantially circular in shape. However, other shapesare contemplated hereby.

The removable portion 204 optionally includes a tab 208 defined by aline of disruption, for example, cut line 210, which initiates andterminates at endpoints 212 proximate to tear line 206. In this example,cut line 210 is substantially arcuate in shape, such that tab 208 issubstantially semi-circular in shape. However, other tab shapes arecontemplated. If desired, tear line 206 may be interrupted by a scoreline 214 that extends substantially between endpoints 212.

Still viewing FIG. 2, the blank 200 also includes a plurality of minorpanels or side panels extending from the base panel 204. Moreparticularly, two pairs of opposed side panels 216 are joined to thebase panel along fold lines 218, each of which corresponds generally toan edge of the substantially octagonal base panel 204. The side panels216 are substantially rectangular in shape, although other shapes arecontemplated hereby. Locking tabs 220 are joined to each end of thevarious side panels 216 along fold lines 222 (only some of the lockingtabs 220 and fold lines 222 are labeled in FIG. 2A). In this example,the locking tabs 220 are somewhat “V” shaped. However, other lockingfeatures or connection mechanisms are contemplated for use with theinvention.

The blank 200 also includes two pairs of opposed side panels 224 joinedto the base panel 204 along fold lines 226, each of which alsocorresponds generally to an edge of the substantially octagonal basepanel 204. Each of the four side panels 224 is arranged in analternating relation with each of the four side panels 216. Side panels224 are separated from locking tabs 220 by cut lines 228 (only some ofwhich are labeled in FIG. 2A).

Each side panel 222 includes a pair of opposed receiving slits 230, eachbeing dimensioned to receive an adjacent locking tab or other lockingfeature 220. In this example, each receiving slit 230 includes a first,substantially linear segment 232 that is substantially perpendicular tothe respective adjacent fold line 226, a second, substantially linearsegment 234 that is substantially parallel to the respective adjacentfold line 226, and a third, inwardly arcuate segment 236 that extendsbetween and substantially joins the first segment 232 and the secondsegment 234 (only one of each of the first, second, and third segments232, 234, 236 are labeled in FIG. 2A). However, other receiving featuresare contemplated by the invention.

If desired, a microwave energy interactive element 238 may overlie atleast a portion of the blank 200, as shown schematically by stippling inFIG. 2A. The microwave energy interactive element 238 may define atleast a portion of a first surface 240 of the blank 200, and may defineat least a portion of a first or inside surface 240 of a construct 242(FIGS. 2B and 2C) formed from the blank 200. In one example, themicrowave energy interactive element comprises a susceptor. However,other microwave energy interactive elements, such as those describedbelow, are contemplated for use with the invention.

To form a tray or construct 242 from the blank 200 according to oneacceptable method, side panels 216, 224 may be folded toward the firstsurface 240 of the blank 200 to form generally upstanding members orwalls. If desired, the various locking tabs 220 may be inserted into therespective adjacent receiving slits 230 to secure the construct 242 inthis configuration, as shown schematically in an inverted position inFIG. 2B. The construct 242 may be used as a tray or package to contain afood item, as discussed above in connection with FIGS. 1B and 1C.

If desired, the removable panel 204 may be separated from the remainderof the construct 242 to form a heating, browning, and/or crisping system244 including a disk 246 and cover or ring 248, as shown schematicallyin FIG. 2C, and may be used to heat, brown, and/or crisp a food item Fin the manner generally described in connection with FIGS. 1C-1E. It isnoted that, in this example, the ring 248 has an overall octagonal shapethat may be more suitable for some microwave ovens that include aturntable and that cannot accommodate the rotation of a square shapedring. Furthermore, where a susceptor 238 is used, the octagonal shape ofring 248 provides greater conformance to the sides of the food item Fand, therefore, may enhance browning and crisping of the sides of thefood item F.

FIG. 3 illustrates another blank 300 that may be used in accordance withthe invention. The blank 300 includes features that are similar to blank200 shown in FIG. 2A, except for variations noted and variations thatwill be understood by those of skill in the art. For simplicity, and notlimitation, the reference numerals of similar features are preceded inthe figures with a “3” instead of a “2”. The blank 300 may be used toform trays, containers, heating systems, and other constructs accordingto the invention and may be used to contain, heat, brown, and/or crisp afood item, as described in connection with FIGS. 1B-1H, with variationsnoted and variations that will be understood by those of skill in theart.

In this example, the blank 300 includes a plurality of microwave energyinactive or transparent areas or “apertures” 350 circumscribed by themicrowave energy interactive element 338. The microwave energy inactiveor transparent areas are somewhat circular in shape and moreconcentrated near a central area 352 of the base panel 302. However,other shapes, numbers, and configurations of microwave energytransparent areas are contemplated. The number, shape, size, andpositioning of such apertures may vary for a particular applicationdepending on type of construct being formed from the blank, the fooditem to be heated therein or thereon, the desired degree of browningand/or crisping, whether direct exposure to microwave energy is neededor desired to attain uniform heating of the food item, the need forregulating the change in temperature of the food item through directheating, and whether and to what extent there is a need for venting. Themicrowave energy transparent areas may be formed in any suitable manner,as will be discussed further below.

The blank 300 also includes a plurality of score lines or indentations354 extending radially from the central area 352 of the base panel 304.In this example, the blank 300 includes eight indentations. However, anynumber of such indentations may be used in accordance with the presentinvention. Such indentations may serve as venting channels, as discussedabove in connection with FIGS. 1A and 1E.

FIG. 4 illustrates another blank 400 that may be used in accordance withthe invention. The blank 400 includes features that are similar to blank200 shown in FIG. 2A, except for variations noted and variations thatwill be understood by those of skill in the art. For simplicity, and notlimitation, the reference numerals of similar features are preceded inthe figures with a “4” instead of a “2”. The blank 400 may be used toform trays, containers, heating systems, and other constructs accordingto the invention and may be used to contain, heat, brown, and/or crisp afood item, as described in connection with FIGS. 1B-1H, with variationsnoted and variations that will be understood by those of skill in theart.

In this example, each side panel 424 includes a pair of substantiallyparallel receiving slits 430, each dimensioned to receive an adjacentlocking tab 420. Each slit 430 is substantially perpendicular to therespective adjacent fold line 426. However, other configurations arecontemplated by the invention. Further, each locking tab 420 isseparated from the adjacent panel 424 by a cutout 450. The precise shapeand dimension of cutout 450 may vary for a particular application.

Numerous other blanks and constructs are contemplated by the invention.Likewise, numerous materials may be suitable for use in forming thevarious blanks and constructs of the invention, provided that thematerials are resistant to softening, scorching, combusting, ordegrading at typical microwave oven heating temperatures, for example,at from about 250° F. to about 425° F. The particular materials used mayinclude microwave energy interactive materials and microwave energytransparent or inactive materials.

For example, any of the various constructs of the present invention mayinclude one or more features that alter the effect of microwave energyduring the heating or cooking of the food item. For instance, as statedabove, the construct include one or more microwave energy interactiveelements (hereinafter sometimes referred to as “microwave interactiveelements”) that promote browning and/or crisping of a particular area ofthe food item, shield a particular area of the food item from microwaveenergy to prevent overcooking thereof, or transmit microwave energytowards or away from a particular area of the food item. Each microwaveinteractive element comprises one or more microwave energy interactivematerials or segments arranged in a particular configuration to absorbmicrowave energy, transmit microwave energy, reflect microwave energy,or direct microwave energy, as needed or desired for a particularmicrowave heating construct and food item.

The microwave interactive element may be supported on a microwaveinactive or transparent substrate for ease of handling and/or to preventcontact between the microwave interactive material and the food item. Asa matter of convenience and not limitation, and although it isunderstood that a microwave interactive element supported on a microwavetransparent substrate includes both microwave interactive and microwaveinactive elements or components, such constructs are referred to hereinas “microwave interactive webs”.

The microwave energy interactive material may be an electroconductive orsemiconductive material, for example, a metal or a metal alloy providedas a metal foil; a vacuum deposited metal or metal alloy; or a metallicink, an organic ink, an inorganic ink, a metallic paste, an organicpaste, an inorganic paste, or any combination thereof. Examples ofmetals and metal alloys that may be suitable for use with the presentinvention include, but are not limited to, aluminum, chromium, copper,inconel alloys (nickel-chromium-molybdenum alloy with niobium), iron,magnesium, nickel, stainless steel, tin, titanium, tungsten, and anycombination or alloy thereof.

Alternatively, the microwave energy interactive material may comprise ametal oxide. Examples of metal oxides that may be suitable for use withthe present invention include, but are not limited to, oxides ofaluminum, iron, and tin, used in conjunction with an electricallyconductive material where needed. Another example of a metal oxide thatmay be suitable for use with the present invention is indium tin oxide(ITO). ITO can be used as a microwave energy interactive material toprovide a heating effect, a shielding effect, a browning and/or crispingeffect, or a combination thereof. For example, to form a susceptor, ITOmay be sputtered onto a clear polymeric film. The sputtering processtypically occurs at a lower temperature than the evaporative depositionprocess used for metal deposition. ITO has a more uniform crystalstructure and, therefore, is clear at most coating thicknesses.Additionally, ITO can be used for either heating or field managementeffects. ITO also may have fewer defects than metals, thereby makingthick coatings of ITO more suitable for field management than thickcoatings of metals, such as aluminum.

Alternatively, the microwave energy interactive material may comprise asuitable electroconductive, semiconductive, or non-conductive artificialdielectric or ferroelectric. Artificial dielectrics comprise conductive,subdivided material in a polymeric or other suitable matrix or binder,and may include flakes of an electroconductive metal, for example,aluminum.

In one example, the microwave interactive element may comprise a thinlayer of microwave interactive material that tends to absorb microwaveenergy, thereby generating heat at the interface with a food item. Suchelements often are used to promote browning and/or crisping of thesurface of a food item (sometimes referred to as a “browning and/orcrisping element”). When supported on a film or other substrate, such anelement may be referred to as a “susceptor film” or, simply,“susceptor”. In the example illustrated in FIG. 1A, the blank 100includes a susceptor film 140 substantially overlying and at leastpartially defining a first surface 142 (e.g. substantially one side) ofthe blank 100. However, other microwave energy interactive elements,such as those described herein, are contemplated hereby.

For example, the microwave interactive element may comprise a foilhaving a thickness sufficient to shield one or more selected portions ofthe food item from microwave energy (sometimes referred to as a“shielding element”). Such shielding elements may be used where the fooditem is prone to scorching or drying out during heating.

The shielding element may be formed from various materials and may havevarious configurations, depending on the particular application forwhich the shielding element is used. Typically, the shielding element isformed from a conductive, reflective metal or metal alloy, for example,aluminum, copper, or stainless steel. The shielding element generallymay have a thickness of from about 0.000285 inches to about 0.05 inches.In one aspect, the shielding element has a thickness of from about0.0003 inches to about 0.03 inches. In another aspect, the shieldingelement has a thickness of from about 0.00035 inches to about 0.020inches, for example, 0.016 inches.

As still another example, the microwave interactive element may comprisea segmented foil, such as, but not limited to, those described in U.S.Pat. Nos. 6,204,492, 6,433,322, 6,552,315, and 6,677,563, each of whichis incorporated by reference in its entirety. Although segmented foilsare not continuous, appropriately spaced groupings of such segmentsoften act as a transmitting element to direct microwave energy tospecific areas of the food item. Such foils also may be used incombination with browning and/or crisping elements, for example,susceptors. As another example, the microwave interactive element maycomprise a foil having a thickness sufficient to shield one or moreselected portions of the food item from microwave energy (sometimesreferred to as a “shielding element”). Such shielding elements may beused where the food item is prone to scorching or drying out duringheating.

The shielding element may be formed from various materials and may havevarious configurations, depending on the particular application forwhich the shielding element is used. Typically, the shielding element isformed from a conductive, reflective metal or metal alloy, for example,aluminum, copper, or stainless steel. The shielding element generallymay have a thickness of from about 0.000285 inches to about 0.05 inches.In one aspect, the shielding element has a thickness of from about0.0003 inches to about 0.03 inches. In another aspect, the shieldingelement has a thickness of from about 0.00035 inches to about 0.020inches, for example, 0.016 inches.

As still another example, the microwave interactive element may comprisea segmented foil, such as, but not limited to, those described in U.S.Pat. Nos. 6,204,492, 6,433,322, 6,552,315, and 6,677,563, each of whichis incorporated by reference in its entirety. Although segmented foilsare not continuous, appropriately spaced groupings of such segmentsoften act as a transmitting element to direct microwave energy tospecific areas of the food item. Such foils also may be used incombination with browning and/or crisping elements, for example,susceptors.

Any of the numerous microwave interactive elements described herein orcontemplated hereby may be substantially continuous, that is, withoutsubstantial breaks or interruptions, or may be discontinuous, forexample, by including one or more breaks or apertures that transmitmicrowave energy therethrough. The breaks or apertures may be sized andpositioned to heat particular areas of the food item selectively. Thenumber, shape, size, and positioning of such breaks or apertures mayvary for a particular application depending on type of construct beingformed, the food item to be heated therein or thereon, the desireddegree of shielding, browning, and/or crisping, whether direct exposureto microwave energy is needed or desired to attain uniform heating ofthe food item, the need for regulating the change in temperature of thefood item through direct heating, and whether and to what extent thereis a need for venting.

It will be understood that the aperture may be a physical aperture orvoid in the material used to form the construct, or may be anon-physical “aperture”. A non-physical aperture may be a portion of theconstruct that is microwave energy inactive by deactivation orotherwise, or one that is otherwise transparent to microwave energy(e.g. apertures 350 in FIG. 3). Thus, for example, the aperture may be aportion of the construct formed without a microwave energy activematerial or, alternatively, may be a portion of the construct formedwith a microwave energy active material that has been deactivated. Whileboth physical and non-physical apertures allow the food item to beheated directly by the microwave energy, a physical aperture alsoprovides a venting function to allow steam or other vapors to bereleased from the food item.

As stated above, any of the above elements and numerous otherscontemplated hereby may be supported on a substrate. The substratetypically comprises an electrical insulator, for example, a polymericfilm or material. As used herein the term “polymer” or “polymericmaterial” includes, but is not limited to, homopolymers, copolymers,such as for example, block, graft, random, and alternating copolymers,terpolymers, etc. and blends and modifications thereof. Furthermore,unless otherwise specifically limited, the term “polymer” shall includeall possible geometrical configurations of the molecule. Theseconfigurations include, but are not limited to isotactic, syndiotactic,and random symmetries.

The thickness of the film typically may be from about 35 gauge to about10 mil. In one aspect, the thickness of the film is from about 40 toabout 80 gauge. In another aspect, the thickness of the film is fromabout 45 to about 50 gauge. In still another aspect, the thickness ofthe film is about 48 gauge. Examples of polymeric films that may besuitable include, but are not limited to, polyolefins, polyesters,polyamides, polyimides, polysulfones, polyether ketones, cellophanes, orany combination thereof. Other non-conducting substrate materials suchas paper and paper laminates, metal oxides, silicates, cellulosics, orany combination thereof, also may be used.

In one example, the polymeric film comprises polyethylene terephthalate(PET). Polyethylene terephthalate films are used in commerciallyavailable susceptors, for example, the QWIKWAVE® Focus susceptor and theMICRORITE® susceptor, both available from Graphic PackagingInternational (Marietta, Ga.). Examples of polyethylene terephthalatefilms that may be suitable for use as the substrate include, but are notlimited to, MELINEX®, commercially available from DuPont Teijan Films(Hopewell, Va.), SKYROL, commercially available from SKC, Inc.(Covington, Ga.), and BARRIALOX PET, available from Toray Films (FrontRoyal, Va.), and QU50 High Barrier Coated PET, available from TorayFilms (Front Royal, Va.).

The polymeric film may be selected to impart various properties to themicrowave interactive web, for example, printability, heat resistance,or any other property. As one particular example, the polymeric film maybe selected to provide a water barrier, oxygen barrier, or a combinationthereof. Such barrier film layers may be formed from a polymer filmhaving barrier properties or from any other barrier layer or coating asdesired. Suitable polymer films may include, but are not limited to,ethylene vinyl alcohol, barrier nylon, polyvinylidene chloride, barrierfluoropolymer, nylon 6, nylon 6,6, coextruded nylon 6/EVOH/nylon 6,silicon oxide coated film, barrier polyethylene terephthalate, or anycombination thereof.

One example of a barrier film that may be suitable for use with thepresent invention is CAPRAN® EMBLEM 1200M nylon 6, commerciallyavailable from Honeywell International (Pottsville, Pa.). Anotherexample of a barrier film that may be suitable is CAPRAN® OXYSHIELD OBSmonoaxially oriented coextruded nylon 6/ethylene vinyl alcohol(EVOH)/nylon 6, also commercially available from HoneywellInternational. Yet another example of a barrier film that may besuitable for use with the present invention is DARTEK® N-201 nylon 6,6,commercially available from Enhance Packaging Technologies (Webster,N.Y.). Additional examples include BARRIALOX PET, available from TorayFilms (Front Royal, Va.) and QU50 High Barrier Coated PET, availablefrom Toray Films (Front Royal, Va.), referred to above.

Still other barrier films include silicon oxide coated films, such asthose available from Sheldahl Films (Northfield, Minn.). Thus, in oneexample, a susceptor may have a structure including a film, for example,polyethylene terephthalate, with a layer of silicon oxide coated ontothe film, and ITO or other material deposited over the silicon oxide. Ifneeded or desired, additional layers or coatings may be provided toshield the individual layers from damage during processing.

The barrier film may have an oxygen transmission rate (OTR) as measuredusing ASTM D3985 of less than about 20 cc/m²/day. In one aspect, thebarrier film has an OTR of less than about 10 cc/m²/day. In anotheraspect, the barrier film has an OTR of less than about 1 cc/m²/day. Instill another aspect, the barrier film has an OTR of less than about 0.5cc/m²/day. In yet another aspect, the barrier film has an OTR of lessthan about 0.1 cc/m²/day.

The barrier film may have a water vapor transmission rate (WVTR) of lessthan about 100 g/m²/day as measured using ASTM F1249. In one aspect, thebarrier film has a water vapor transmission rate as measured using ASTMF1249 of less than about 50 g/m²/day. In another aspect, the barrierfilm has a WVTR of less than about 15 g/m²/day. In yet another aspect,the barrier film has a WVTR of less than about 1 g/m²/day. In stillanother aspect, the barrier film has a WVTR of less than about 0.1g/m²/day. In a still further aspect, the barrier film has a WVTR of lessthan about 0.05 g/m²/day.

Other non-conducting substrate materials such as metal oxides,silicates, cellulosics, or any combination thereof, also may be used inaccordance with the present invention.

The microwave energy interactive material may be applied to thesubstrate in any suitable manner, and in some instances, the microwaveenergy interactive material is printed on, extruded onto, sputteredonto, evaporated on, or laminated to the substrate. The microwave energyinteractive material may be applied to the substrate in any pattern, andusing any technique, to achieve the desired heating effect of the fooditem.

For example, the microwave energy interactive material may be providedas a continuous or discontinuous layer or coating including circles,loops, hexagons, islands, squares, rectangles, octagons, and so forth.Examples of various patterns and methods that may be suitable for usewith the present invention are provided in U.S. Pat. Nos. 6,765,182;6,717,121; 6,677,563; 6,552,315; 6,455,827; 6,433,322; 6,414,290;6,251,451; 6,204,492; 6,150,646; 6,114,679; 5,800,724; 5,759,422;5,672,407; 5,628,921; 5,519,195; 5,424,517; 5,410,135; 5,354,973;5,340,436; 5,266,386; 5,260,537; 5221,419; 5,213,902; 5,117,078;5,039,364; 4,963,424; 4,936,935; 4,890,439; 4,775,771; 4,865,921; andRe. 34,683, each of which is incorporated by reference herein in itsentirety. Although particular examples of patterns of microwave energyinteractive material are shown and described herein, it should beunderstood that other patterns of microwave energy interactive materialare contemplated by the present invention.

The microwave interactive element or microwave interactive web may bejoined to or overlie a dimensionally stable, microwave energytransparent support (hereinafter referred to as “microwave transparentsupport”, “microwave inactive support” or “support”) to form theconstruct.

In one aspect, for example, where a rigid or semi-rigid construct is tobe formed, all or a portion of the support may be formed at leastpartially from a paperboard material, which may be cut into a blankprior to use in the construct. For example, the support may be formedfrom paperboard having a basis weight of from about 60 to about 330lbs/ream, for example, from about 80 to about 140 lbs/ream. Thepaperboard generally may have a thickness of from about 6 to about 30mils, for example, from about 12 to about 28 mils. In one particularexample, the paperboard has a thickness of about 12 mils. Any suitablepaperboard may be used, for example, a solid bleached or solidunbleached sulfate board, such as SUS® board, commercially availablefrom Graphic Packaging International.

In another aspect, where a more flexible construct is to be formed, thesupport may comprise a paper or paper-based material generally having abasis weight of from about 15 to about 60 lbs/ream, for example, fromabout 20 to about 40 lbs/ream. In one particular example, the paper hasa basis weight of about 25 lbs/ream.

Optionally, one or more portions of the various blanks or otherconstructs described herein or contemplated hereby may be coated withvarnish, clay, or other materials, either alone or in combination. Thecoating may then be printed over with product advertising or otherinformation or images. The blanks or other constructs also may be coatedto protect any information printed thereon.

Furthermore, the blanks or other constructs may be coated with, forexample, a moisture and/or oxygen barrier layer, on either or bothsides, such as those described above. Any suitable moisture and/oroxygen barrier material may be used in accordance with the presentinvention. Examples of materials that may be suitable include, but arenot limited to, polyvinylidene chloride, ethylene vinyl alcohol, DuPontDARTEK™ nylon 6,6, and others referred to above.

Alternatively or additionally, any of the blanks or other constructs ofthe present invention may be coated or laminated with other materials toimpart other properties, such as absorbency, repellency, opacity, color,printability, stiffness, or cushioning. For example, absorbentsusceptors are described in U.S. Provisional Application No. 60/604,637,filed Aug. 25, 2004, and U.S. patent application Ser. No. 11/211,858, toMiddleton, et al., titled “Absorbent Microwave Interactive Packaging”,filed Aug. 25, 2005, both of which are incorporated herein by referencein their entirety. Additionally, the blanks or other constructs mayinclude graphics or indicia printed thereon.

It will be understood that with some combinations of elements andmaterials, the microwave interactive element may have a grey or silvercolor this is visually distinguishable from the substrate or thesupport. However, in some instances, it may be desirable to provide aweb or construct having a uniform color and/or appearance. Such a web orconstruct may be more aesthetically pleasing to a consumer, particularlywhen the consumer is accustomed to packages or containers having certainvisual attributes, for example, a solid color, a particular pattern, andso on. Thus, for example, the present invention contemplates using asilver or grey toned adhesive to join the microwave interactive elementsto the substrate, using a silver or grey toned substrate to mask thepresence of the silver or grey toned microwave interactive element,using a dark toned substrate for example, a black toned substrate, toconceal the presence of the silver or grey toned microwave interactiveelement, overprinting the metallized side of the web with a silver orgrey toned ink to obscure the color variation, printing thenon-metallized side of the web with a silver or grey ink or otherconcealing, color in a suitable pattern or as a solid color layer tomask or conceal the presence of the microwave interactive element, orany other suitable technique or combination thereof.

If desired, a combination of paper layers, polymer film layers, andmicrowave interactive elements may be used to form a microwave energyinteractive insulating material or structure. As used herein, the terms“microwave energy interactive insulating material”, “microwave energyinteractive insulating structure”, “microwave interactive insulatingmaterial”, “microwave interactive structure”, “insulating material”, or“insulating structure” refer any arrangement or combination of layers ofmaterials that is both responsive to microwave energy and capable ofproviding some degree of thermal insulation when used to heat a fooditem.

An insulating material may be used to form all or a portion of a blankor construct according to the present invention. For example, all or aportion of the microwave energy interactive elements 140, 238, 338, 438shown schematically by stippling in FIGS. 1A-4 may comprise a microwaveenergy interactive insulating material. Although FIGS. 1A-4schematically illustrate a microwave energy interactive elements 140,238, 338, 438 defining substantially all of the respective firstsurfaces 142, 240, 340, 440 of the various blanks 100, 200, 300, 400 andconstructs 144, 242, 244, it will be understood that the microwaveenergy interactive insulating material may overlie only a portion of theblank or construct according to the invention.

Where an insulating material overlies the removable panel or portion ofthe construct, and therefore, the heating, browning, and/or crispingcard or disk, it will be understood that the user may be instructed toplace the food item on the side of the disk overlying the insulatingmaterial or on the opposite side, such that the insulating materialrests on the floor of the microwave oven. The precise instructionsprovided to the user may depend on the desired degree of heating,browning, crisping, and thermal insulation for the particular food item,or may depend on numerous other factors.

In one aspect, the insulating material or structure comprises one ormore susceptor layers in combination with one or more expandableinsulating cells. Additionally, the insulating material may include oneor more microwave energy transparent or inactive materials to providedimensional stability, to improve ease of handling the microwave energyinteractive material, and/or to prevent contact between the microwaveenergy interactive material and the food item. For example, aninsulating material may comprise a microwave energy interactive materialsupported on a first polymeric film layer, a moisture-containing layersuperposed with the microwave energy interactive material, and a secondpolymeric film layer joined to the moisture-containing layer in apredetermined pattern, thereby forming one or more closed cells betweenthe moisture-containing layer and the second polymeric film layer. Theclosed cells expand or inflate in response to being exposed to microwaveenergy, thereby causing the microwave energy interactive structure tobulge and deform.

Several exemplary insulating materials are depicted in FIGS. 5A-8B. Itwill be understood that the layer widths are not necessarily shown inperspective. In some instances, for example, the adhesive layers may bevery thin with respect to other layers, but are nonetheless shown withsome thickness for purposes of clearly illustrating the arrangement oflayers.

FIG. 5A depicts an exemplary microwave energy interactive insulatingmaterial 500 that may be suitable for use with the various aspects ofthe invention. In this example, a thin layer of microwave energyinteractive material that serves as a susceptor 502 is supported on afirst polymer film 504 (collectively forming a “susceptor film”) andbonded by lamination with an adhesive 506 (or otherwise) to adimensionally stable substrate 508, for example, paper. The substrate508 is bonded to a second polymer film 510 using a patterned adhesive512 or other material, thereby forming a plurality of expandableinsulating cells 514. The insulating material 500 may be cut andprovided as a substantially flat, multi-layered sheet 516, as shown inFIG. 5B.

As the susceptor 502 heats upon impingement by microwave energy, watervapor and other gases typically held in the substrate 508, for example,paper, and any air trapped within the closed cells 514 between thesecond polymer film 510 and the substrate 508, expand, as shown in FIG.5C. The resulting insulating material 516′ has a quilted or pillowed orlofted top surface 518 and bottom surface 520. When microwave heatinghas ceased, the cells 514 typically deflate and the insulating structurereturns to a somewhat flattened state.

If desired, the insulating material 500 may be modified to form astructure 522 that includes an additional paper or polymer film layer524 joined to the first polymer film layer 504 using an adhesive 526 orother suitable material, as shown in FIG. 5D.

FIG. 6 illustrates another exemplary insulating material 600. Thematerial 600 includes a polymer film layer 602, a susceptor layer 604,an adhesive layer 606, and a paper layer 608. Additionally, the material600 may include a second polymer film layer 610, an adhesive 612, and apaper layer 614. The layers may be adhered or affixed by a patternedadhesive 616 that defines a plurality of closed expandable cells 618.

FIG. 7 illustrates yet another exemplary insulating material 700 thatmay be suitable for use with the invention. In this example, theinsulating material 700 includes a pair of adjoined, symmetrical layerarrangements. If desired, the two symmetrical arrangements may be formedby folding one layer arrangement onto itself.

The first symmetrical layer arrangement, beginning at the top of thedrawing, comprises a polymer film layer 702, a susceptor layer 704, anadhesive layer 706, and a paper or paperboard layer 708. The adhesivelayer 706 bonds the polymer film 702 and the susceptor layer 704 to thepaperboard layer 708.

The second symmetrical layer arrangement, beginning at the bottom of thedrawing, also comprises a polymer film layer 710, a susceptor layer 712,an adhesive layer 714, and a paper or paperboard layer 716. A patternedadhesive layer 718 is provided between the two paper layers 708, 716,and defines a pattern of closed cells 720 configured to expand whenexposed to microwave energy.

By using an insulating material 700 having respective susceptors 704,712 on each side of the expandable insulating cells 720, more heat isgenerated, thereby achieving greater loft of the cells 720. As a result,such a material is able to elevate a food item seated thereon to agreater extent than an insulating material having a single susceptorlayer.

It will be recognized that each of the exemplary insulating materialsdepicted in FIGS. 5A-7 include a moisture-containing layer (e.g. paper)that is believed to release at least a portion of the vapor thatinflates the expandable cells. However, it is contemplated thatstructures that are adapted to inflate without such moisture-containinglayers also may be used in accordance with the invention.

FIG. 8A illustrates one example of an expandable cell insulatingmaterial 800 that is adapted to inflate without the use of amoisture-containing layer, for example, paper. In this example, one ormore reagents are used to generate a gas that expands the cells of theinsulating material. For example, the reagents may comprise sodiumbicarbonate (NaHCO₃) and a suitable acid. When exposed to heat, thereagents react to produce carbon dioxide. As another example, thereagent may comprise a blowing agent. Examples of blowing agents thatmay be suitable include, but are not limited to,p-p′-oxybis(benzenesulphonylhydrazide), azodicarbonamide, andp-toluenesulfonylsemicarbazide. However, it will be understood thatnumerous other reagents and released gases are contemplated hereby.

In the example shown in FIG. 8A, a thin layer of microwave interactivematerial 802 is supported on a first polymer film 804 to form asusceptor film 806. One or more reagents 808, optionally within acoating, lie adjacent at least a portion of the layer of microwaveinteractive material 802. The reagent 808 coated susceptor film 806 isjoined to a second polymer film 810 using a patterned adhesive 812 orother material, or using thermal bonding, ultrasonic bonding, or anyother suitable technique, such that closed cells 814 (shown as a void)are formed in the material 800.

As discussed in connection with the other exemplary insulatingmaterials, as the microwave interactive material 802 heats uponimpingement by microwave energy, water vapor or other gases are releasedfrom or generated by the reagent 808. The resulting gas applies pressureon the susceptor film 806 on one side and the second polymer film 810 onthe other side of the closed cells 814. Each side of the material 800reacts simultaneously, but uniquely, to the heating and vapor expansionto form a pillowed or quilted insulating material 800′ (FIG. 8B). Thisexpansion may occur within 1 to 15 seconds in an energized microwaveoven, and in some instances, may occur within 2 to 10 seconds. Evenwithout a paper or paperboard layer, the water vapor resulting from thereagent is sufficient both to inflate the expandable cells and to absorbany excess heat from the microwave energy interactive material. Suchmaterials are described further in U.S. Patent Application PublicationNo. 20060289521A1, which is incorporated by reference herein in itsentirety.

It will be understood that any of the microwave energy interactiveinsulating materials described herein or contemplated hereby may includean adhesive pattern or thermal bond pattern that is selected to enhancecooking of a particular food item. For example, where the food item is alarger item, the adhesive pattern may be selected to form substantiallyuniformly shaped expandable cells. Where the food item is a small item,the adhesive pattern may be selected to form a plurality of differentsized cells to allow the individual items to be variably contacted ontheir various surfaces. While several examples are provided herein, itwill be understood that numerous other patterns are contemplated hereby,and the pattern selected will depend on the heating, browning, crisping,and insulating needs of the particular food item.

If desired, multiple layers of insulating materials and other microwaveenergy interactive elements may be used to enhance the insulatingproperties of the insulating material and, therefore, enhance thebrowning and crisping of the food item. Where multiple layers are used,the layers may remain separate or may be joined using any suitableprocess or technique, for example, thermal bonding, adhesive bonding,ultrasonic bonding or welding, mechanical fastening, or any combinationthereof. In one example, two sheets of an insulating material may bearranged so that their respective susceptor film layers are facing awayfrom each other. In another example, two sheets of an insulatingmaterial may be arranged so that their respective susceptor film layersare facing towards each other. In still another example, multiple sheetsof an insulating material may be arranged in a like manner andsuperposed. In a still further example, multiple sheets of variousinsulating materials are superposed in any other configuration as neededor desired for a particular application. Thus, for example, aninsulating material may be superposed with one or more additional layersof susceptors or susceptor films.

While various examples of constructs are provided herein, it will beunderstood that any configuration of components may be used as needed ordesired. The construct may be flexible, semi-rigid, rigid, or mayinclude a variety of components having different degrees of flexibility.Additionally, it should be understood that the present inventioncontemplates constructs for single-serving portions and formultiple-serving portions. It also should be understood that variouscomponents used to form the constructs of the present invention may beinterchanged. Thus, while only certain combinations are illustratedherein, numerous other combinations and configurations are contemplatedhereby.

Although certain embodiments of this invention have been described witha certain degree of particularity, those skilled in the art could makenumerous alterations to the disclosed embodiments without departing fromthe spirit or scope of this invention. All directional references (e.g.,upper, lower, upward, downward, left, right, leftward, rightward, top,bottom, above, below, vertical, horizontal, clockwise, andcounterclockwise) are used only for identification purposes to aid thereader's understanding of the various embodiments of the presentinvention, and do not create limitations, particularly as to theposition, orientation, or use of the invention unless specifically setforth in the claims. Joinder references (e.g., joined, attached,coupled, connected, and the like) are to be construed broadly and mayinclude intermediate members between a connection of elements andrelative movement between elements. As such, joinder references do notnecessarily imply that two elements are connected directly and in fixedrelation to each other.

It will be recognized by those skilled in the art, that various elementsdiscussed with reference to the various embodiments may be interchangedto create entirely new embodiments coming within the scope of thepresent invention. It is intended that all matter contained in the abovedescription or shown in the accompanying drawings shall be interpretedas illustrative only and not limiting. Changes in detail or structuremay be made without departing from the spirit of the invention. Thedetailed description set forth herein is not intended nor is to beconstrued to limit the present invention or otherwise to exclude anysuch other embodiments, adaptations, variations, modifications, andequivalent arrangements of the present invention.

Accordingly, it will be readily understood by those persons skilled inthe art that, in view of the above detailed description of theinvention, the present invention is susceptible of broad utility andapplication. Many adaptations of the present invention other than thoseherein described, as well as many variations, modifications, andequivalent arrangements will be apparent from or reasonably suggested bythe present invention and the above detailed description thereof,without departing from the substance or scope of the present invention.

While the present invention is described herein in detail in relation tospecific aspects, it is to be understood that this detailed descriptionis only illustrative and exemplary of the present invention and is mademerely for purposes of providing a full and enabling disclosure of thepresent invention and to provide the best mode contemplated by theinventor or inventors of carrying out the invention. The detaileddescription set forth herein is not intended nor is to be construed tolimit the present invention or otherwise to exclude any such otherembodiments, adaptations, variations, modifications, and equivalentarrangements of the present invention.

1. A blank for forming a construct, comprising: a main panel including aremovable panel at least partially defined by a line of disruption; aplurality of side panels extending from the main panel along respectivefold lines; and a microwave energy interactive element overlying atleast a portion of the main panel.
 2. The blank of claim 1, wherein themain panel includes a peripheral portion that circumscribes theremovable panel.
 3. The blank of claim 1, further comprising a tabdefined by a line of disruption that initiates and terminates proximatethe removable panel.
 4. The blank of claim 1, wherein the main panel issubstantially square in shape, and the plurality of side panels includesa first pair of opposed side panels that are substantially rectangularin shape, and a second pair of opposed side panels that aresubstantially trapezoidal in shape.
 5. The blank of claim 4, furthercomprising a pair of end panels extending from opposed ends of each sidepanel of the first pair of side panels.
 6. The blank of claim 1, whereinthe plurality of side panels includes a first side panel including apair of locking tabs extending from opposed ends of the first sidepanel, and a second side panel including a pair of receiving slits, eachreceiving slit being adapted to receive one locking tab of the pair oflocking tabs.
 7. The blank of claim 1, wherein the plurality of panelsincludes a first set of side panels and a second set of side panelsextending from the main panel in an alternating relationship, each sidepanel of the first set of side panels includes a pair of locking tabs,and each side panel of the second set of side panels includes a pair ofreceiving slits adapted to receive the respective adjacent locking tabs.8. The blank of claim 7, wherein the main panel is substantiallyoctagonal in shape, the first set of side panels includes four sidepanels, and the second set of side panels includes four side panels. 9.The blank of claim 1, wherein the microwave energy interactive elementcomprises a susceptor.
 10. The blank of claim 1, wherein the microwaveenergy interactive element circumscribes a plurality of microwave energytransparent areas.
 11. A construct for containing, heating, browning,and/or a crisping a food item, comprising: a base and a plurality ofwalls defining an interior space; and a microwave energy interactivematerial overlying at least a portion of the base proximate the interiorspace, wherein the base includes a removable panel defined at leastpartially by a line of disruption, and a peripheral area circumscribingthe removable panel.
 12. The construct of claim 11, wherein theconstruct is adapted to receive a food item seated on the base withinthe interior space.
 13. The construct of claim 11, wherein the microwaveenergy interactive material overlies at least a portion of the removablepanel, the removable panel is adapted to be separated from theconstruct, and with the removable panel separated from the construct,the removable panel is adapted to receive at least a portion of the fooditem intended to be browned and/or crisped.
 14. The construct of claim11, wherein the microwave energy interactive material overlies at leasta portion of the peripheral area of the base, the food item includes aperipheral area intended to be browned and/or crisped, and in aconfiguration with the walls extending downwardly from the base, theconstruct is adapted to receive the food item within the interior spacewith the microwave energy interactive material overlying the peripheralarea of the food item.
 15. The construct of claim 11, wherein the baseis substantially square in shape, and the plurality of walls includes afirst pair of opposed walls that are substantially rectangular in shape,and a second pair of opposed walls that are substantially trapezoidal inshape.
 16. The construct of claim 15, further comprising a pair of endpanels extending from opposed ends of each wall of the first pair ofwalls.
 17. The construct of claim 11, wherein the plurality of wallsincludes a first set of walls and a second set of walls in analternating relationship extending from the main panel, each wall of thefirst set of walls includes a pair of locking tabs, and each wall of thesecond set of walls includes a pair of receiving slits adapted toreceive the respective adjacent locking tabs.
 18. A multi-use constructcomprising: a base and a plurality of walls defining an interior space,the base including a removable panel defined by a line of disruption;and a microwave energy interactive element overlying at least a portionof the base and defining at least a portion of an interior surface,wherein the construct is adapted to be transitioned between a firstconfiguration with the walls extending upwardly from the base, such thatthe construct is adapted to contain a food item within the interiorspace, a second configuration with the removable panel separated fromthe base, such that the removable panel is adapted to receive at least aportion of the food item, and a third configuration with the removablepanel separated from the base to form a remaining portion of theconstruct, in which the remaining portion of the construct is adapted tobe inverted relative to the first configuration and positioned over thefood item.
 19. The construct of claim 18, wherein the removable panelhas a first side at least partially comprising at least a portion of themicrowave energy interactive element, the food item has a surfaceintended to be browned and/or crisped, and in the second configuration,the surface of the food item intended to be browned and/or crisped is ina superposed, facing relationship with the first side of the removablepanel.
 20. The construct of claim 18, wherein the base includes aperipheral area circumscribing the removable panel, the microwave energyinteractive element overlies at least a portion of the peripheral area,and in the third configuration, the peripheral area overlies a portionof the food item intended to be browned and/or crisped.
 21. Theconstruct of claim 18, wherein the removable panel separated from thebase forms an opening in the base, and in the third configuration, theopening overlies a portion of the food item not intended to be brownedand/or crisped.
 22. A method of heating, browning, and/or crisping afood item in a microwave oven, comprising: providing a container havinga base including a removable portion defined at least partially by aline of disruption, wherein the removable portion includes a microwaveenergy interactive material; separating the removable portion from thebase to form a remaining portion; and placing the food item on theremovable portion.
 23. The method of claim 22, wherein the remainingportion comprises a microwave energy interactive material, and themethod further comprises positioning the remaining portion over the fooditem, such that the food item is disposed between the removable portionand the remaining portion.
 24. A method of heating, browning, and/orcrisping a food item in a microwave oven, comprising: providing acontainer including a base and a plurality of substantially upstandingwalls that define a cavity for receiving a food item, wherein the baseincludes a removable portion and a peripheral portion circumscribing theremovable portion, and a microwave energy interactive material overliesat least a portion of the removable portion and at least a portion ofthe peripheral portion; separating the removable portion from theperipheral portion, thereby forming a remainder of the construct;placing the food item on the removable portion; and inverting theremainder of the construct and placing it over the food item, such thatthe food item is disposed between the removable portion and theremainder of the construct.